Pr2O3/RuO2和Gd2O3/RuO2对甲醇的选择性电催化氧化性能研究

由于电解水阳极析氧反应(Oxygen Evolution Reaction, OER)过电位较高,增加了电解水制氢的整体能耗。故本实验采用热力学上有利的甲醇氧化反应(Methanol Oxidation Reaction, MOR)替代OER,尝试缓解OER对酸性电解水制氢的能耗制约。通过热解法制备了Pr₂O₃/RuO₂和Gd₂O₃/RuO₂催化剂,不仅能催化甲醇生成增值的甲酸(HCOOH),而且可以使MOR过程与析氢反应耦合,生成高纯的H₂。电化学分析测试表明,在含CH₃OH(2.5 mol·L^-1)的H₂SO₄(0.5 mol·L^-1)电解质溶液中,电流密度达到10 mA·cm^-2时,Pr₂O₃/RuO₂和Gd₂O...     

MnOx?FeOy/TiO2?ZrO2?CeO2低温选择性催化还原NOz和抗毒性研究

用溶胶凝胶法制备TiO₂?ZrO₂?CeO₂（摩尔比4∶1∶1.25）载体,柠檬酸溶液浸渍法进一步负载MnO_x及MnO_x?FeO_y,进而合成了一种Fe掺杂的新型Mn基复合氧化物催化剂,考察其NH₃选择性催化还原NO性能及抗硫性能。它在含硫氛围中有良好的低温选择性催化还原（SCR）能力和抗中毒能力,Fe的引入促进了Mn与TiO₂?ZrO₂?CeO₂载体之间的相互作用,增加了催化剂表面Lewis酸性位点的数量。根据X射线光谱分析,Mn4+,Ce4+和吸附的氧的含量明显增加,对提高催化剂的性能非常有利。根据热重分析,在SO₂和H₂O同时存在的环境下,Fe的存在使硫酸铵和硫酸铈的产生量减少,抑制了锰的硫酸化,进一步提高了催化剂的抗毒性。MnO_x（12.5%）?FeO_y（0.8）/TiO₂?ZrO₂?CeO₂（4∶1∶1.25）催化剂在180 ℃下,同时通入体积分数10% H₂O和125×10?6 SO₂ 240 min,NO_z转化率可保持在75.6%。根据研究成果,新型锰基复合金属氧化物催化剂为进一步探索催化剂的SCR反应和抗毒机理提供了基础,促进了SCR工艺的工业应用。      

Catalytic combustion of toluene on Pt/Al2O3 and Pd/Al2O3 catalysts with CeO2,CeO2-Y2O3 and La2O3 as coatings

CeO₂,La₂O₃,and CeO₂-Y₂O₃ oxides were coated on the surface of spherical granular AI₂O₃(3-5 mm)through impregnation method,and proved as better supports of Pd and Pt catalysts.The influences of rare earth metal doping on the adsorption rates of Pd and Pt ions,as well as the catalytic performance,were investigated.Results show that the H₂PtCl₆·6H₂O adsorption rates of the Al     

等离子喷涂Sc2O3、Gd2O3和Y2O3复合稳定ZrO2热障涂层相稳定性及导热性研究

采用化学共沉淀-煅烧法制备了Sc2O3、Gd2O3和Y2O3复合稳定ZrO2陶瓷原粉,陶瓷原粉经球磨、团聚造粒和烧结处理后得到适于等离子喷涂工艺的热喷涂粉末。测试分析了Sc2O3、Gd2O3和Y2O3复合稳定ZrO2热喷涂粉末微观形貌、流动性及其等离子喷涂涂层的相稳定性及导热性。结果表明Sc2O3、Gd2O3和Y2O3复合稳定ZrO2材料及其等离子喷涂涂层具有优异的高温相稳定性,即使在1400℃热处理500小时依然呈四方相结构、无单斜相出现,涂层热导率比单一Y2O3稳定ZrO2涂层明显降低,Sc2O3、Gd2O3和Y2O3复合稳定ZrO2可以用作新型超高温热障涂层材料。     

O2/CO2气氛下煤粉燃烧数值模拟

采用CFD技术对不同气氛下煤粉燃烧过程进行了研究。用Fluent软件模拟不同工况下煤粉燃烧,获得煤粉燃烧的一些基础性参数,为实际应用提供相应的指导;建立包括气相湍流流动、气固之间传热、煤挥发分析以及燃烧等过程在内的三维数学模型;将不同气氛下煤粉燃烧的特性进行对比,研究气氛变化对燃烧的影响规律。     

CaO–Al2O3–SiO2复合烧结助剂添加量对ZrO2/Al2O3复相陶瓷性能的影响

以Al(NO₃)₃·9H₂O、Ca(NO)₂·4H₂O、C₈H₂₀O₄Si为原料, 采用高分子网络法制备出成分均匀、粒度分布为3~7μm、高活性的CaO–Al₂O₃–SiO₂复合烧结助剂; 将质量分数为3%、5%、7%、9%的CaO–Al₂O₃–SiO₂复合烧结助剂添加到Al₂O₃和ZrO₂原料粉体中, 经干压成型, 在1450℃烧结温度、保温4h的工艺条件下进行常压烧结制备得到ZrO₂/Al₂O₃复相陶瓷试样, 研究烧结助剂添加量对复相陶瓷力学性能和显微组织结构的影响。结果表明:当添加质量分数为5%的CaO–Al₂O₃–SiO₂复合烧结助剂时, ZrO₂/Al₂O₃复相陶瓷的综合性能最达到佳, 相对密度为94%, 显微维氏硬度为1204 MPa, 抗弯强度为321 MPa, 断裂韧性为4.52 MPa·m1/2。     

Al2O3/LiAlO2协同提升LiNi0.92Co0.04Mn0.04O2正极材料循环稳定性的研究

锂离子电池(LIBs)是最普遍的储能设备之一,高镍LiNi_0.92Co_0.04Mn_0.04O₂正极因其放电比容量高而备受关注,然而,在长循环的过程中,由于正极表面的活性物质发生了化学和结构变化,LIBs的能量存储能力会随着循环的进行而减弱。理解和缓解这些退化机制是减少容量衰退的关键,从而提高锂离子电池的循环寿命。包覆是常见的改性手段,可改善高镍LiNi_0.92Co_0.04Mn_0.04O₂正极界面稳定性并降低表面降解的程度。但是,常规包覆方法形成的包覆层的厚度和均匀性难以调控,为了改进此问题,本研究建立了一种Al₂O₃/LiAlO₂薄膜,对LiNi_0.92Co_0.04Mn_0.04O₂具有协同改性效应,可形成厚度均匀的双包覆层,增强正极材料的循环性能和结构稳定性。研...     

TiO2掺杂CeO2催化超声降解甲基橙

以合成TiO2掺杂CeO2作为催化剂,以超声降解甲基橙反应为模型,研究了各种因素对TiO2掺杂CeO2催化超声降解甲基橙溶液的影响。结果表明,在TiO2(掺杂CeO2)催化剂作用下超声降解甲基橙的效果明显优于单纯以锐钛矿型TiO2催化时的情况。TiO2(掺杂CeO2)用量为0.5 g/L～1.0 g/L、超声波频率为25 kHz、输出功率为1.0 W/cm2、pH值为1.0～3.0时,初始浓度为20 mg/L的甲基橙水溶液在80 min左右基本可降解完全,COD的去除率达到了99.0%。     

Ag2C2O4/TiO2异质结的制备及其光催化性能研究

采用溶胶-凝胶法制备了锐钛矿型TiO₂,通过沉淀法成功将Ag₂C₂O₄沉积于TiO₂表面制备了Ag₂C₂O₄/TiO₂异质结。采用孔隙比表面分析仪(BET)、X-射线衍射仪(XRD)等对Ag₂C₂O₄/TiO₂异质结结构和光响应能力进行了表征;运用表面光电压仪(SPS)等对光催化剂的光生电荷分离特性进行了研究;考察了异质结光催化剂对模拟污染物罗丹明B的催化降解性能。结果表明：当Ag₂C₂O₄/TiO₂摩尔比为7.0%时,异质结光催化剂的光生电子-空穴分离速率最高,该光催化剂对罗丹明B的光催化降解性能最好。     

低碱度含FeO渣热分解H2O/CO2制取H2/CO

以转炉钢渣为原料,通过高温重熔获得不同碱度渣样并开展H₂O/CO₂氧化试验,在获得H₂/CO气体能源的同时改善渣样磁性,提升渣综合利用率。试验结果表明,随着碱度增加,析出主要物相从橄榄石到镁蔷薇辉石最终向硅酸二钙转变,与此同时,固溶在其中的RO相逐渐溶出。相同亚铁含量下,高碱度渣样能够大幅度改善氧化反应效率,碱度1.83渣样最高产气量为H₂ (32.3 cm3/g)、CO (22.1 cm3/g),反应率分别达到了83.7%、57%,碱度1.13的渣样反应率分别仅为 40.5%、32%。氧化后的渣样磁选效率均有提高,碱度2.13渣样从14.85%增加到78.75%。     

Catalytic Partial Oxidation of Methane over Ni/CeO2-ZrO2-Al2O3

Nickel catalysts supported on CeO2-ZrO2-CeO2,ZrO2-Al2O3 and Al2O3 were prepared and characterized by means of X-ray diffraction（XRD）,BET areas,H2 temperature-programmed reduction（H2-TPR）,and X-ray photoelectron spectroscopy（XPS）.Through the test of catalytic partial oxidation of methane（CPOM）,Ni/CeO2-ZrO2-Al2O3 displayed the highest activity,which resulted from its largest BET area and best NiO dispersion.Furthermore,Ni/CeO2-ZrO2-Al2O3 maintained a long-time stability in CPOM,which was attributed to its best coking resistance among all the prepared catalysts.     

CaO--TiO2--Fe2O3三元系中Ca3TiFe2O8的生成机理

钒钛磁铁矿是烧结矿重要的原料之一,Ca₃TiFe₂O₈作为钒钛烧结矿中矿物被发现之后,其生成机理尚不明确.本文采用X射线衍射分析、元素能谱分析和TG-DSC分析相结合的方法,研究了Ca₃TiFe₂O₈的生成机理以及不同温度、CaO与TiO₂含量下Ca₃TiFe₂O₈的生成规律.实验结果表明,Ca₃TiFe₂O₈由Ca₂ Fe₂O₅和CaTiO₃反应生成,即CaO和Fe₂O₃反应生成Ca₂ Fe₂O₅;其后,与CaTiO₃反应生成Ca₃TiFe₂O₈.反应时间越长,Ca₃TiFe₂O₈的生成量越大,但反应温度对Ca₃TiFe₂O₈生成的影响并不明显.另外,还发现CaO含量越高,Ca₃TiFe₂O₈越易于生成,而且等摩尔Fe₂O₃和CaO下只要存在TiO₂,就会有Ca₃TiFe₂O₈生成.      

Effect of Fe2O3 Loading Amount on Catalytic Properties of Monolithic Fe2O3/Ce0.67Zr0.33O2 -Al2O3 Catalyst for Methane Combustion

Ce0.67Zr0.33O2-Al2O3 solid solution was prepared by the co-precipitation method. Fe2O3-based catalysts supported on the solid solution were obtained by the impregnation method. The article revealed that the optimal loading amount of Fe2O3 on Ce0.67Zr0.33 O2-Al2O3 in our experimental condition for catalytic combustion of methane was 8% （ mass fraction）. The prepared catalysts were characterized by BET, TPR, XRD analyses, and their catalytic activity was investigated after being calcined at 873 K and after being aged in water gas at 1273 K. When the loading amount of Fe203 was 8% （ mass fraction）, the catalyst held the highest activity, and the best temperature speciality and thermal stability. The complete-conversion temperature of methane for fresh and aged sample was 788 and 838 K, respectively. The range between the light-off temperature and the complete-conversion temperature was only 15 K. The characterization results of XRD indicated that Fe2O3 was well dispersed on the Ce0.67Zr0.33O2-Al2O3 matrix. The results of BET and TPR were in good harmony with the catalytic activity results.     

Superconducting Transition Temperature in YBa2Cu4O8/La2/3 Ca1/3 MnO3 / YBa2 Cu4O8 Heterostructure

YBa2Cu4O8/La2/3 Ca1/3 MnO3/YBa2Cu4O8 （ Y-124/LCMO/Y- 124） heterostructure was prepared by facing-target sputtering technique. The oscillatory superconducting transition temperature was observed when the thickness of LCMO d L is larger than critical thickness d L^CR. The metal-insulator transition temperature can only be detected at d L 〉 d L^CR. The dependence on the spacer layer in LCMO/Y-124 systems suggests strongly the interplay of ferromagnetic and superconducting couplings.     

SnCl2－HgCl2－K2Cr2O7容量法测定的矿石中TFe时HgCl2用量的选择

为了保持应用已久的有汞测铁经典方法中的许多优点而减轻HgCl2对环境的污染的缺点,对方法中HgCl2的用量由5m^[1]减少为2ml进行理论上的探讨,并以试验结果加以论证。     

Study on thermal expansion behavior of Dy2O3 - Al2O3 - SiO2 glass

Employing Dy2O3, Al2O3, and SiO2 as starting materials, several series of Dy2O3-Al2O3-SiO2 sealing glass were prepared. The relationship between their coefficients of thermal expansion and the contents of Dy2O3, Al2O3, and SiO2 were studied respectively. Experimental results showed that Dy2O3 and Al2O3 had a positive effect on the coefficient of thermal expansion of glass, whereas, SiO2 had a negative effect. The coefficient of thermal expansion of glass showed an apparent linear relation to the contents of these three raw materials, from which an estimation model was built, to calculate the coefficient of thermal expansion of sealing glass. Relative errors of the calculating results to testing results were no more than 2%, which suggested that the estimation model was reasonable. This study provides a good theory reference for the practical utilizing of this sealing material, through which a proper glass composition for good sealing could be easily found.     

Synthesis and Crystal Structure of A Bimetallic Terbium Complex Tb2 {μ-CH2 SiMe2 NC6 H3 ^iPr2 -2, 6}3 （THF）3

The reaction of 2, 6-^iPr2CbH3NHSiMe3 with Tb（CH2SiMe3）3（THF）2 in benzene at room temperature afforded a binuclear terbium complex Tb2 {μ-CH2 SiMe2 NC6 H3 ^iPr2 -2, 6}3（THF）3. X-ray diffraction revealed that Tb atoms were bridged by three methylene units. One Tb atom was six-coordinated by two nitrogen atoms, three methylene carbons, and one THF molecule, while the other Tb atom was six-coordinated by one nitrogen atom, three methylene carbons, and two THF molecules. Both Tb atoms adopted a distorted trigonal prism geometry.     

Promotional effect of CeO2 and Y2O3 on CuO/ZrO2 catalysts for methane combustion

Catalytic combustion of methane was conducted by using a Cu-based catalyst prepared by the plasma-assisted impregnation method. The properties of the catalysts were surveyed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (H2-TPR). The results showed that the activity of CuO/ZrO2 with the CeO2 and Y2O3 was obviously increased compared with the CuO/ZrO2 catalyst, which was examined in relation to the structure and surface characteristics and might be correlated with their surface oxygen species and redox properties. Among the investigated catalysts, the Ce-CuO/ZrO2 sample exhibited the highest activity for methane combustion.     

WSi2／MoSi2复合粉末材料的机械合金化合成

通过机械合金化和热处理工艺成功地制备了MoSi2 50%（摩尔分数x）WSi2复合粉末材料，利用X射线衍射手段分析了相的形成过程，并从热力学和球磨能量角度比较了MoSi2和WSi2相生成的难易程度。球磨40h后在高于1000℃热处理可获得（Mo,W)Si2合金；因G^0(MoSi2)＜G^0(WSi2),WSi2相较MoSi2难生成，其所需球磨能量分别为120．240kJ/g和30．060kJ/g。     

Effects of La2O3/Li2O/TiO2- Coating on Electrochemical Performance of LiCoO2 Cathode

Conventional cathode material （LiCoO2） was modified by coating with a thin layer of La2O3/Li2O/TiO2 for improving its performance for lithium ion battery. The morphology and structure of the modified cathode material was characterized by SEM, XRD, and Auger electron spectroscopy. The performance of the cells with the modified cathode material was examined, including the cycling stability, the diffusion coefficient under different voltages, and the C-rate discharge. The results showed that the cell composed of the coated cathode material discharged at a large current density, and possesses a stable cycle performance in the range from 3.0 to 4.4 V. It was explained that the rate of Li ion diffusion increased in the cell while using La2O3/Li2O/TiO2-coated LiCoO2 as the cathode and the coating layer may act as a faster ion conductor （La2O3/Li2O/TiO2）.